A seal arrangement which defines the species is known, for example, from DE 32 18 255 A1. A seal arrangement of this kind is provided for operation in a so-called Scotch yoke engine, which is characterized among other things by the fact that piston rods between the working piston and the crank mechanism move only in a straight line along their longitudinal axes. In such engines, the crankcase is usually separated from the cylinder chambers by a partition wall and the piston rod passes through this partition wall in the region of a through opening.
Particularly in two-stroke internal combustion engines, this opens up the possibility of using a cylinder chamber between the partition wall and the piston, which chamber is sealed on the side oriented toward the crankcase, as an option for supercharging the engine, i.e. using this chamber as a charging pump for supercharging the engine.
The reference cited above proposes guiding the piston rod in the radial direction by means of a guide sleeve in the region of the partition wall opening, thereby providing it with a definite support. A single sealing ring is proposed, which is embodied in the form of an internally clamping sealing ring and is seated in a ring element. With regard to the through opening, the sealing ring is situated on the cylinder side of the Scotch yoke engine so that the guide sleeve supporting the piston rod in the radial direction can also be supplied with oil from the crankcase. This seal has in fact proven its worth. It has particularly proven its worth for use in gasoline or diesel engines. It has not always been able, however, to completely prevent oil from escaping from the crankcase into the cylinder chamber since the one sealing ring proposed must not only produce a seal preventing gas pressures from the cylinder chamber from escaping in the direction of the crankcase, but must also perform the function of stripping off oil that has been carried out of the crankcase and through the guide sleeve by the piston rod.
The object of the invention, therefore, is to propose an arrangement for sealing reciprocating piston machine piston rods that extend through partition walls, that is particularly suitable for use in high-speed reciprocating piston machines, in particular engines and compressors of the Scotch yoke type, which prevents to the greatest extent possible the escape of oil from the crankcase into a cylinder chamber on the one hand and prevents to the greatest extent possible losses in gas pressure from a cylinder chamber, which is delimited for example by the piston bottom and a partition wall of the reciprocating piston machine, and to provide a further optimized sealing action. In particular, it is also important for this seal to be embodied in a simple way, with a small number of separate parts. In particular, it should be easily possible to replace the sealing rings that produce the sealing action. Particular focus should be placed on the possibility of preassembling the seal arrangement in modular fashion.
Furthermore, the invention should in particular be suitable for use in high-speed engines in which the maximum piston velocity of approximately 20 to 26 m/sec can occur, which likewise corresponds to the maximum piston rod velocity. In particular, a seal arrangement should be proposed, which is suitable for reciprocating piston machines that are preferably embodied as gasoline engines, preferably used in stationary operation, i.e. with engine speeds that change only slightly in long-term operation.